From: Pavel Machek <pavel@ucw.cz>
To: linux-leds@vger.kernel.org, dmurphy@ti.com
Subject: ledtrig-cpu: Limit to 4 CPUs
Date: Sat, 19 Sep 2020 11:38:33 +0200 [thread overview]
Message-ID: <20200919093833.GA14326@duo.ucw.cz> (raw)
[-- Attachment #1: Type: text/plain, Size: 2039 bytes --]
commit 318681d3e019e39354cc6c2155a7fd1bb8e8084d
Author: Pavel Machek <pavel@ucw.cz>
Date: Sat Sep 19 11:34:58 2020 +0200
ledtrig-cpu: Limit to 4 CPUs
Some machines have thousands of CPUs... and trigger mechanisms was not
really meant for thousands of triggers. I doubt anyone uses this
trigger on many-CPU machine; but if they do, they'll need to do it
properly.
Signed-off-by: Pavel Machek <pavel@ucw.cz>
diff --git a/drivers/leds/trigger/ledtrig-cpu.c b/drivers/leds/trigger/ledtrig-cpu.c
index 869976d1b734..b7e00b09b137 100644
--- a/drivers/leds/trigger/ledtrig-cpu.c
+++ b/drivers/leds/trigger/ledtrig-cpu.c
@@ -2,14 +2,18 @@
/*
* ledtrig-cpu.c - LED trigger based on CPU activity
*
- * This LED trigger will be registered for each possible CPU and named as
- * cpu0, cpu1, cpu2, cpu3, etc.
+ * This LED trigger will be registered for first four CPUs and named
+ * as cpu0, cpu1, cpu2, cpu3. There's additional trigger called cpu that
+ * is on when any CPU is active.
+ *
+ * If you want support for arbitrary number of CPUs, make it one trigger,
+ * with additional sysfs file selecting which CPU to watch.
*
* It can be bound to any LED just like other triggers using either a
* board file or via sysfs interface.
*
* An API named ledtrig_cpu is exported for any user, who want to add CPU
- * activity indication in their code
+ * activity indication in their code.
*
* Copyright 2011 Linus Walleij <linus.walleij@linaro.org>
* Copyright 2011 - 2012 Bryan Wu <bryan.wu@canonical.com>
@@ -145,6 +149,9 @@ static int __init ledtrig_cpu_init(void)
for_each_possible_cpu(cpu) {
struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
+ if (cpu > 4)
+ continue;
+
snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu);
led_trigger_register_simple(trig->name, &trig->_trig);
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]
next reply other threads:[~2020-09-19 9:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-19 9:38 Pavel Machek [this message]
2020-09-20 14:15 ` ledtrig-cpu: Limit to 4 CPUs Jacek Anaszewski
2020-09-20 15:39 ` Marek Behun
2020-09-20 16:55 ` Jacek Anaszewski
2020-09-20 17:33 ` Marek Behun
2020-09-20 17:49 ` Jacek Anaszewski
2020-09-20 18:34 ` Pavel Machek
2020-09-21 22:14 ` Jacek Anaszewski
2020-09-21 22:42 ` Pavel Machek
2020-09-22 20:41 ` Jacek Anaszewski
2020-09-25 8:51 ` Jacek Anaszewski
2020-09-25 9:40 ` Pavel Machek
2020-09-26 13:59 ` Jacek Anaszewski
2020-10-08 10:10 ` Pavel Machek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200919093833.GA14326@duo.ucw.cz \
--to=pavel@ucw.cz \
--cc=dmurphy@ti.com \
--cc=linux-leds@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).